Serotonergic system dysfnctionhas been associated with impulsive/aggression in a variety of populations from clinical personality disordered patients to criminal offenders, as consistently as any neurotransmitter-behavioral association in biologic psychiatry. The impulsive/aggression of personality disorder patients, in particular, poses a critical challenge to the clinical psychiatrist because of its attendeant occupational and interpersonal consequences. The objectives of the proposed studies are to evaluate cerebral metabolism in regions of interest implicated in inhibition/modulation of aggressive behavior.